University of WA scientists are this week gearing up to catch a glimpse of the atmosphere of Saturn’s largest moon — Titan — and carry out a raft of measurements, including to see if there are any tell-tale signs of extraterrestrial life.

A cosmic ballet will play out on Wednesday evening, just after 11pm, when Titan passes in front of a brightly lit star, resulting in what astronomers refer to as an “occultation” that illuminates the moon’s atmosphere from behind.

Similar to a lunar eclipse, when the moon passes between our planet and the Sun, the phenomenon will cast a shadow across Earth’s surface — and right through WA.

UWA associate professor David Coward with the uni's Zadko telescope in Gingin. Credit:UWA

To study this rare event, UWA scientists will join forces with counterparts from the German SOFIA Institute to observe and measure Titan’s atmosphere from two different locations.

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SOFIA — or Stratospheric Observatory for Infrared Astronomy — is in reality a converted Boeing 747SP with a huge 2.5-metre telescope in the back of it, allowing scientists to peer at the stars from above the clouds.

On Wednesday night, Karsten Schindler and the rest of the SOFIA team will fly the modified plane through the centre of the shadow Titan casts on Earth, with researchers given an eight-minute window as it moves from east to west across Australia.

At the same time, UWA associate professor David Coward and his team will be busy at the university’s super-sensitive Zadko telescope in Gingin, 80km north of Perth, also taking measurements of Titan’s atmosphere as it moves in front of the star.

A map outlining the plan for Wednesday's observation: the yellow marker is the location of the UWA Zadko telescope; the other blue markers are other collaborators who will support observations from the ground. The red line is the center line of Titan's shadow, the two black lines are the northern and southern limb of Titan, which has a diameter of a bout 5200km. The light blue line is the preliminary flight path of SOFIA out of Christchurch, as it flies to make its observation on the leg that intercepts the red line.Credit:UWA

All of the information gathered will then be pored over by scientists, who will study changes and growth in the moon’s “dense” atmosphere, its relationship with Saturn — and whether there could be any tell-tale signs of organic life.

Mr Schindler explained the atmosphere, rich in nitrogen and very dense, made it unique among its peers in the solar system. The last opportunity to measure Titan using a similar method was in 2003.

NASA’s Cassini space probe also measured Titan, but that mission came to the end of its life in September 2017, finishing with the probe diving into Saturn’s clouds and ultimately getting destroyed.

Titan, Saturn's largest moon appears before the planet as it undergoes seasonal changes in this natural-colour view from NASA's Cassini spacecraft.Credit:NASA

“What puzzles astronomers is that on larger timescales like many years you see pressure changes and changes in the extent [size] of the atmosphere, so it’s important to monitor that over many years,” Mr Schindler said.

“(Changes in the atmosphere) probably comes down to geological processes and whether (Titan) can be basically in a feedback with Saturn, with Saturn’s gravity pulling on the moon.”

But as alien as Titan is, it is still very familiar to us — Professor Coward said conditions on the moon were similar to what Earth was like at a young age.

"One of the controversies, and why Karsten is here, is that the atmosphere that was measured previously on Titan had a different extent — had a different size," he said.

"The idea is; what is changing Titan’s atmosphere?

"That is a very important question, there could be geological processes, and also there could be life on Titan."

We can’t say whether life is creating this atmosphere in Titan, but we’re very interested in changes in a planet or a moon’s atmosphere.

UWA associate professor David Coward

It all comes down to what’s on Titan’s surface. Currently, scientists believe there is an ocean of liquid water buried under frozen methane gas.

Professor Coward said that made for a “very unique mixture”, with some of those “exotic” chemicals like methane dominating Earth in its early years.

"So the earth’s atmosphere has changed over millions of years from this very hostile environment to something that we’ve got now because of life," he said.

"We can’t say whether life is creating this atmosphere in Titan, but we’re very interested in changes in a planet or a moon’s atmosphere."

Little green men they may not be, but little microbes giving off methane gas would be tantalising for astronomers searching the skies for any sign of company in our galactic neighbourhood.

"I know many people speculate about life on Titan – I personally would be a little bit careful about that, you never know — of course, there could be some organism that produces some kind of gas, but I would say it comes down more to the geology side of the planet," Mr Schindler said.

"I guess the driving factor is always if you have a dense atmosphere, for example, in such a body that is much further out in the solar system, would it sustain conditions in terms of temperature that might enable life — of course that is one of the questions."

But for the ground-based UWA team, a spanner in the works comes in the form of the weather.

There is only a four-minute window for the Gingin telescope to observe Titan as it passes in front of the star, and if cloud cover happens to sweep over then their view to the sky is blocked.

However, if all goes well then it is another achievement of WA scientists working in tandem with cutting-edge global research.

The facility the Zadko telescope is housed at also plays host to UWA’s OzGrav research facility — the same team that played a key role in the momentous discovery of gravitational waves in 2015.

It also bolsters WA’s contribution to the nation’s science output, and strengthens the case for the state to house an arm of the recently announced Australian Space Agency in the future.

“This is really big science, and for UWA to be involved in that in any way has to be important for us to be involved in these projects for the future,” Professor Coward said.

“We see this as a growth and getting more involved in these projects — this is a springboard.”